2001 GMC Sierra 1500 Pickup Owner's Manual - Page 362

CAUTION: Operating the engine with the air cleaner/filter off can cause you or others to be burned. The air cleaner not only cleans the air, it stops flame if the engine backfires. If it isn't there, and the engine backfires, you could be burned. Don't drive with it off, and be careful working on the engine with the air cleaner/filter off. Passenger Compartment Air Filter (If Equipped) Your vehicle may be equipped with a passenger compartment air filter. The filter is located under the instrument panel, below the glove compartment. Your vehicle may or may not be equipped with an access panel. To replace the passenger compartment air filter, do the following: 1. If your vehicle has an access panel, remove the bolts on it and set the panel aside. If your vehicle does not have the access panel, skip this step. 2. Next, pull downward on the filter retaining bracket. NOTICE: If the air cleaner/filter is off, a backfire can cause a damaging engine fire. And, dirt can easily get into your engine, which will damage it. Always have the air cleaner/filter in place when you're driving. 6-20